Arty voltage regulator failures

[jhauser-us]

I feel I must let people know that, based on my own experience, the
Arty boards have a higher than expected failure rate for the external
12-volt power regulator.  The symptom of this failure is that the board
ceases to work with the external power supply.  The board can then be
powered only from the USB cable.  This is a disadvantage because the
USB cable can't provide nearly as much power as the external supply.

My first Arty failed within the warranty period, and Digilent was very
quick to replace it.  Now, after a few more weeks, this replacement
board has failed exactly the same way.  A friend of mine in another
town also ordered an Arty board, and his failed the same way.  For my
friend and I, that's a 100% failure rate on 3 boards.  And there have
been at least a couple of other reports in these forums of identical
failures.  All of these failures have been using the power supply that
Digilent sells with the board.

I'm sure Digilent's engineers are as much distressed by these problems
as I am.  But the upshot is that I can't justify buying another Arty
board without some official announcement that the problem has been
solved.

I really like my Arty Z7-20 otherwise, so I'm sorry to be the bearer of
bad news.  Now I will have to replace my Arty with some other board I
like less.

Regards,

    -  John H.

[JColvin]

Hi @jhauser-us,

I am also concerned to hear this since I don't get to hear very often about that side of the business. Which particular Arty were you and your friend using (the original Arty or the Arty Z7-20) and do you happen to remember what revisions the boards were so that I can make sure from my end that the appropriate engineers are looking into this with the information they need?

Additionally, is there anything unique about your power supply or is it a fairly standard 12V-3A supply with a center positive plug? What sort of designs were you working with, i.e. smaller designs with some basic I/O and logic, or some larger designs that used HDMI and other components that draw a lot more current?

Thank you,
JColvin

[jhauser-us]

Hi JColvin,

First off, here are the two other postings I was referring to:
https://forum.digilentinc.com/topic/9042-arty-z7-020-regulator-failure/
https://forum.digilentinc.com/topic/9755-spi-bootloader-guide-blew-up-arty-board/

On further review, I can't tell whether the second posting is the same
problem.  But the first one reports exactly the same issue as I've
seen.  That was an Arty Z7-20, and so were mine and my friend's three
boards.  So perhaps the failures are occurring for only one particular
manufacturing batch of the Arty Z7-20s.

Here's what I told Digilent support when I reported the failure of my
first board, still under warranty at the time:

Quote

Unfortunately, I've experienced a premature failure.  Yesterday, I
had the board powered on using your power brick, with only the USB and
Ethernet connected, running Digilent's version of PetaLinux obtained from
here,
https://reference.digilentinc.com/reference/software/petalinux/start
when the board spontaneously shut off.  Since that moment, it has not
been possible to power the Arty Z7-20 from the power brick.  The board
appears completely dead in that configuration.  For what it's worth, the
board can still be powered from the USB cable, and appears to operate
normally that way.

The evidence suggests that an on-board voltage regulator chip
(specifically IC24) had a short life, and burned up, or something
around it did.  I cannot rule out the possibility that the power brick
is defective and caused an overload, though that's perhaps unlikely.

The only external power supply that my friend and I have used with the
boards is this one that Digilent sells for use with the Arty Z7-20:
https://store.digilentinc.com/12v-3a-power-supply/

I'm not sure how to identify the board revision, but these were boards
that Digilent shipped out in late March and mid April.  On the board I
have now, there are a couple of stickers with numbers on them.  One is
00183E027733, and the other is DA5C4D8.  Does that help?

Surely there must be some people still successfully using their
Arty Z7-20s, or we would've heard more of these stories.  But, as I
said, my own personal experience is 100% failure.  I don't know how my
friend and I got so unlucky.

Regards,

    - John H.

[aminorrrrrrr@gmail.com]

Hi John,

Hopefully moderator will approve this. It's unethical not to.

I ordered two units of Arty-Z7-20 for my personal use (from your serial I guess mine is later version). I never got the chance to test all of the device modules onboard immediately except for programming and powering the FPGA through USB-JTAG. But recently I tried to power up one of the board using external PSU and my power supply was cut-off on OCP. And I checked for continuity test and it gave a very low resistance on the Power module input port. Furthermore I tested several resistors around the power module and most of them gave no readings / no conductivity response at all compared to my other Arty-Z7-20 (no faulty). No sign or burn whatsoever. I guess there might be a defective power input coaxial port on solder or components.  am not sure how long the Warranty covered by Digilent for this item. Purchased on Feb this year. and just noticed it last week. I guess Digilent have the responsibility to call back several batch of their Arty series for replacement.

My serial : 

0018-3E02-792D

DA5C68C

And I am surprised that your and your friend's Arties also encountered problem with the power module at that rate from Digilent. I guess this problem is just within Arty series. When I 1st knew Digilent I had purchased severals two units of Digilent High End Dev kit from local distributor Cytron Malaysia respectively : NetFPGA-SUME Virtex-7 FPGA Dev. Board & NetFPGA-1G-CML Kintex-7 FPGA Dev. Board. And I have got no complaint yet from my researchers. And I hope Digilent wont ignore their client claim for their obvious faulty.

[JColvin]

So that other readers of this thread are aware, we are working with aminorrrrrrr through the RMA process off of this main thread.

Thanks,
JColvin